Information processing apparatus and method program, and recording medium

ABSTRACT

An encoded bit stream having a frame rate of 24 Hz or 23.976 Hz and a progressive format for both NTSC and PAL is recorded on a recording medium. An encoded stream reproduced from the recording medium is supplied to a decoder  20 . In the decoder  20 , the encoded stream is decoded and 24 p or 23.976 p video is obtained. A video converting portion  25  converts the reproduced video into a display video in accordance with the display format of a monitor  26 . For the NTSC range, 29.97 i or 59.94 p display format can be used. For the PAL range, 25 i or 50 p display format can be used.

TECHNICAL FIELD

The present invention relates to an information processing apparatus anda method for recording sub data that is reproduced in synchronizationwith main audio and video data and to a program for the informationprocessing apparatus and a recording medium on which the program for theinformation processing apparatus is recorded.

BACKGROUND ART

A technology for recording a transport stream of video data that hasbeen encoded in accordance with MPEG2 (Moving Picture Experts GroupPhase 2) to a recording medium for example an optical disc is describedin for example Patent Document 1 (Japanese Patent Laid-Open PublicationNo. 2002-158972).

FIG. 1 shows a picture format of a frame structure of which a videosignal is encoded in accordance with the MPEG. In FIG. 1, dirk stripesrepresent lines of a top field (top_field), whereas white stripesrepresent lines of a bottom field (bottom_field). In the NTSCtransmission picture signal format having an aspect ratio of (4:3), oneframe has a total of 480 lines of 240 lines of the top field and 240lines of the bottom field. The number of pixels in the horizontaldirection is 704 pixels. One bit flag top_field_first of headerinformation of the picture layer represents which of the top field andbottom field is chronologically first displayed. When top_field_first=1,the top field is chronologically first displayed.

FIG. 2 shows a spatial relation between the format of an MPEG decodedpicture and the format of a transmission picture. The format of thetransmission picture is the NTSC format having an aspect ratio of 4:3.An effective pixel area (pixel area of an MPEG decoded picture) of oneframe is composed of 780 pixels×480 lines. The transmission pictureformat includes non-effective areas of a horizontal blanking area and avertical blanking area.

In addition to the foregoing flag top_field_first, another flagrepeat_first_field is also transmitted. The flag repeat_first_field is aflag that represents that there is a repeat field. A film material suchas a movie is data composed of 24 frames per second. In contrast, avideo signal for example an NTSC format video signal has a format of 30frames pre second. Thus, when a film material is converted into a videosignal, a process for generating 30 frames using 24 frames is required.Such a process includes a process for converting two fields into threefields in accordance with a predetermined conversion pattern. Thus, sucha process is generally referred to as 2:3 pull down. In other words, thefirst field is automatically and repeatedly generated twice every fiveframes. As a result, 24 frames are converted into 30 frames.

When a video signal that has been obtained by the foregoing 2:3 pulldown process is compressed in accordance with the MPEG, sinceinformation of fields (repeat fields) that have been inserted forincreasing the number of frames is redundant, the video signal isencoded so that the repeat fields are removed and the compressionefficiency is improved. A process for detecting repeat fields of videodata of which 24 frames per second are converted into 30 frames persecond by the 2:3 pull down process, removing the repeat fields, anddecreasing the number of frames to 24 frames per second is referred toas inverse 2:3 pull down process.

Next, with reference to FIG. 3, the process for converting a filmmaterial of 24 frames per second into an NTSC format television materialof 30 frames per second, namely the 2:3 pull down process, will bedescribed. A film material is composed of two frames per second. Twofields (first and second fields) of the same picture are composed ofeach field of the film material. As a result, a picture signal of 48fields per second is generated. Thereafter, four frames (eight fields)of the film material are converted into five frames (10 fields) of avideo signal, for example an NTSC format video signal.

In FIG. 3, a chronologically last field of three fields surrounded by atrapezoid is a field that is repeated to increase the number of fields,namely a repeat first field. The repeat first field takes place twiceevery five frames. The video signal for which the 2:3 pull down processhas been performed is accompanied by two flags top_field_first andrepeat_first_field. In the frame first structure, the flagtop_field_first is a flag that represents whether the first field is topor bottom. The flag repeat_first_field is a flag that represents thatthere is a repeat field.

As described above, when a video signal is encoded in accordance withthe MPEG2 and the frame frequency of the NTSC format is 29.97 Hz, valuesof the two flags top_field_first and repeat_first_field are set for eachpicture. In addition, frame_rate of the sequence header is set for 29.97Hz.

As another television format, PAL format is also known as well as theNTSC format. The PAL format whose aspect ratio is (4:3) has a framefrequency of 25 Hz and a structure of which one frame is composed of 720(pixels)×576 (lines). In the PAL format, basically, top_field_first=1,repeat_first_field=0, and frame_rate of the sequence header=25 Hz areset. In other words, a top field and a bottom field are made of oneframe of a movie. The obtained video signal is recorded on a recodingmedium. Thus, in the PAL format, the reproduction speed of the videosignal is faster than that of the original movie by 25/24 times.

As described above, in a standard resolution format, the NTSC format isdifferent from the PAL format in the picture size and the frame rate.However, in for example a high resolution (HD: High Definition) format,the picture size of the NTSC format is the same as that of the PALformat. Thus, when a movie source is converted into a video signal ineach format, it is necessary to convert only the frame rate. These twoformats whose frame rates are different and whose picture sizes arecommon are referred to as NTSC range and PAL range.

Conventionally, the format of an original video signal converted into anNTSC video signal was different from the format of an original videosignal converted into a PAL video signal. Thus, to author a recordingmedium on which for example a movie source is recorded, video signalsthat can be suitably converted into both the formats should be prepared.Thus, it was laborious to handle video signals in both the formats.

Recently, a progressive format display monitor has been used. So far, inthe NTSC format, it was difficult to convert a 29.97 Hz interlacedmoving picture into a 59.94 (=2×30×(1000/1001)) Hz progressive movingpicture and display the converted picture. Since a video signal forwhich the 2:3 pull down process had been performed may have beenirregularly encoded, it was not easy to detect a progressive frame froma decoded moving picture of an MPEG2 video stream.

In addition, in the PAL format, a movie source of 24 frames per secondis fast reproduced at a frame rate of 25 Hz. Thus, the reproductionspeed of a video signal is faster than that of an original movie by25/24 times. As a result, the pitch of audio becomes high.

Thus, an object of the present invention is to provide an informationprocessing apparatus and method, a program, and a recording medium thatallow encoding to be performed in common with the NTSC range and the PALrange, a moving picture of the NTSC range to be easily converted into a59.94 Hz progressive moving picture, and a reproduction speed of the PALrange to be prevented from being increased by 25/24 times over that ofthe original.

DISCLOSURE OF THE INVENTION

To solve the foregoing problem, claim 1 of the present invention is aninformation processing apparatus for recording a video signal that canbe displayed at all frame rates of 29.97 Hz, 59.94 Hz, 25 Hz, and 50 Hzon a recording medium, comprising:

-   -   compression encoding means for generating an encoded video bit        stream having a size in common with an NTSC range and a PAL        range, a frame rate of 24 Hz or 23.976 Hz, and a progressive        format; and    -   recording means for recording the encoded video bit stream on        the recording medium.

Claim 2 of the present invention is an information processing method forrecording a video signal that can be displayed at all frame rates of29.97 Hz, 59.94 Hz, 25 Hz, and 50 Hz on a recording medium, comprisingthe steps of:

-   -   generating an encoded video bit stream having a size in common        with an NTSC range and a PAL range, a frame rate of 24 Hz or        23.976 Hz, and a progressive format; and    -   recording the encoded video bit stream on the recording medium.

Claim 3 of the present invention is a program for an informationprocessing apparatus for recording a video signal that can be displayedat all frame rates of 29.97 Hz, 59.94 Hz, 25 Hz, and 50 Hz on arecording medium, the program comprising the steps of:

-   -   generating an encoded video bit stream having a frame rate of 24        Hz or 23.976 Hz and a progressive format; and    -   recording the encoded video bit stream on the recording medium.

Claim 4 of the present invention is a recording medium on which acomputer readable program for an information processing apparatus forrecording a video signal displayed at a frame rate of 29.97 Hz, 59.94Hz, 25 Hz, or 50 Hz is recorded, the program comprising the steps of:

-   -   generating an encoded video bit stream having a size in common        with an NTSC range and a PAL range, a frame rate of 24 Hz or        23.976 Hz, and a progressive format; and    -   recording the encoded video bit stream on the recording medium.

Claim 5 of the present invention is a recording medium on which a videosignal that can be displayed at all frame rates of 29.97 Hz, 59.94 Hz,25 Hz, and 50 Hz is recorded as a compression encoded video bit streamhaving a size in common with an NTSC range and a PAL range, a frame rateof 24 Hz or 23.976 Hz, and a progressive format.

Claim 6 of the present invention is an information processing apparatusfor reproducing from a recording medium a compression encoded video bitstream having a picture size in common with an NTSC range and a PALrange, a frame rate of 24 Hz or 23.976 Hz, and a progressive format, theinformation processing apparatus comprising:

-   -   means for reproducing the encoded video bit stream from the        recording medium;    -   decompression decoding means for decoding the reproduced encoded        video bit stream and generating a video signal having a frame        rate of 23.976 Hz or 24 Hz and a progressive format; and    -   video converting means for converting an output of the        decompression decoding means into a video signal having a frame        rate of 29.97 Hz, 59.94 Hz, 25 Hz, or 50 Hz.

Claim 15 of the present invention is a program for an informationprocessing apparatus for reproducing from a recording medium acompression encoded video bit stream having a picture size in commonwith an NTSC range and a PAL range, a frame rate of 24 Hz or 23.976 Hz,and a progressive format, the program comprising the steps of:

-   -   reproducing the encoded video bit stream from the recording        medium;    -   decoding the reproduced encoded video bit stream and generating        a video signal having a frame rate of 23.976 Hz or 24 Hz and a        progressive format; and    -   converting a video signal obtained at the decompression decoding        step into a video signal having a frame rate of 29.97 Hz, 59.94        Hz, 25 Hz, or 50 Hz.

Claim 16 of the present invention is a recording medium on which acomputer readable program for an information processing apparatus forreproducing from a recording medium a compression encoded video bitstream having a picture size in common with an NTSC range and a PALrange, a frame rate of 24 Hz or 23.976 Hz, and a progressive format isrecorded, the program comprising the steps of:

-   -   reproducing the encoded video bit stream from the recording        medium;    -   decoding the reproduced encoded video bit stream and generating        a video signal having a frame rate of 23.976 Hz or 24 Hz and a        progressive format; and    -   converting a video signal obtained at the decompression decoding        step into a video signal having a frame rate of 29.97 Hz, 59.94        Hz, 25 Hz, or 50 Hz.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram describing an MPEG decoding pictureformat.

FIG. 2 is a schematic diagram describing a relation of the format of anMPEG decoding picture and the format of a transmission picture.

FIG. 3 is a schematic diagram describing a conventional 2:3 pull downprocess.

FIG. 4A and FIG. 4B are schematic diagrams describing a format on a discaccording to an embodiment of the present invention.

FIG. 5 is a block diagram showing an encoder system according to theembodiment of the present invention.

FIG. 6 is a block diagram showing a decoder system according to theembodiment of the present invention.

FIG. 7 is a schematic diagram describing a display format convertingprocess for a video signal according to the embodiment of the presentinvention.

FIG. 8 is a schematic diagram describing a converting process from 24 pinto 30 i and a converting process from 24 p into 60 p.

FIG. 9 is a schematic diagram describing a converting process from23.976 p into 29.97 i and a converting process from 23.976 p into 59.94p.

FIG. 10A and FIG. 10B are schematic diagrams describing a convertingprocess from 24 p into 29.97 i and a converting process from 24 p into59.94 p.

FIG. 11 is a schematic diagram describing a converting process from 24 pinto 25 i and a converting process from 24 p into 50 p.

FIG. 12A and FIG. 12B are schematic diagrams showing a convertingprocess from 23.976 p into 25 i and a converting process from 23.976 pinto 50 p.

FIG. 13 is a flow chart showing a flow of a process of a reproducingmethod applied for the NTSC range according to the present invention.

FIG. 14 is a flow chart showing a flow of a process of a reproducingmethod applied for the PAL range according to the present invention.

BEST MODES FOR CARRYING OUT THE INVENTION

Next, with reference to the accompanying drawings, an embodiment of thepresent invention will be described. According to the present invention,it is assumed that the video format (for example, MPEG2 format) for arecording medium is a 24 Hz (or 23.976 Hz (=24×(1000/1001) Hz)progressive format. On the other hand, as shown in FIG. 4A, as HD videotelevision formats of effective picture area H×V (1920×1080), 29.97 i(interlaced video signal having a frame rate of 29.97 Hz) for the NTSCrange and 25 i (interlaced video signal having a frame rate of 25 Hz)for the PAL range have been standardized.

According to the present invention, as shown in FIG. 4B, for both theNTSC range and the PAL range, for example an MPEG2 video bit stream isrecorded on a recoding medium in a 24 p or 23.976 p (a progressive videosignal having a frame rate of 24 Hz or 23.976 Hz) video format. Thepresent invention can be also applied to another picture size(1440×1080) of an HD video signal.

Conventionally, as shown in FIG. 4A, for effective picture area H×V(1280×720), 59.94 p (a progressive video signal having a frame rate of59.94 Hz) and 50 p (a progressive video signal having a frame rate of 50Hz) have been standardized as HD video television formats for the NTSCrange and the PAL range, respectively.

In this case, according to the present invention, as shown in FIG. 4B,for both the NTSC range and the PAL range, for example an MPEG2 videobit stream is recorded on a recoding medium in 24 p or 23.976 p videoformat. A frame rate, 24 Hz, of a video format for a recording mediumcorresponds to 24 frames per second of an original movie source. A framerate, 23.976 Hz, is a frequency at which a display signal of a monitorcan be easily converted into a frame rate of 29.97 Hz of a displaysignal of a monitor. In other words, there is a relation of (23.976Hz×(5/4)=29.97 Hz). Thus, the 2:3 pull down process for converting theframe rate of 24 Hz into the frame rate of 30 Hz can be used as it is.

On a player side that reproduces from a recording medium a movie sourcewhose frame rate has been converted and for which an encoding processfor example an MPEG2 encoding process have been performed, reproducedvideo data is converted into a video format in accordance with firstdetermination that represents whether the video format of the recordingmedium is 24 p or 23.976 p and second determination that representswhether the display video format of a display monitor (for the NTSCrange) is 29.97 i or 59.94 p or that (for the PAL range) is 25 i or 50p.

Next, the embodiment of the present invention will be described. In FIG.5, reference numeral 10 represents an MPEG2 video encoder. As an inputsignal, a 24 Hz (or 23.976 Hz) digital progressive video signal producedfrom a movie source film is prepared. The input video signal can beproduced in the following two methods.

As the first method, a movie source of 24 frames per second is convertedinto a 24 Hz (or 23.976 Hz) progressive video signal. As the secondmethod, a movie source is converted into a 30 Hz (or 29.97 Hz)interlaced video signal by the 2:3 pull down process. Thereafter, theinterlaced video signal is inversely converted by the inverse 2:3 pulldown process. As a result, a 24 Hz (or 23.976 Hz) progressive videosignal is restored. When the first and second methods are compared, thefirst method is preferable because the amount of the process is small.Since there is a relation of 23.976 Hz (=24×(1000/1001) Hz), when the 24Hz progressive video signal is thinned out by one frame from every 1001frames, a 23.976 Hz progressive video signal can be generated.

The MPEG2 video encoder 10 encodes the input video signal and outputs anMPEG2 video bit stream having the following parameters.

-   -   frame_rate=24 Hz (or 23.976 Hz)    -   progressive_sequence=1    -   top_field_first=0, repeat_first_field=0

The value of frame_rate is the same as the frame rate of the input videosignal (24 Hz or 23.976 Hz).

As shown in FIG. 5, an MPEG2 video bit stream (V) is multiplexed with anaudio stream (A) and system information (S) by a multiplexer 11. As aresult, the multiplexer 11 outputs a transport stream. An ECC (ErrorCorrection Code) encoding portion 12 performs an error correction codeencoding process for the transport stream. A modulating portion 13performs a digital modulating process for an output of the ECC encodingportion 12. An output of the modulating portion 13 is supplied to awriting portion 14. The writing portion 14 records an output of themodulating portion 13 on a recording medium, for example an optical disc15.

FIG. 6 shows a structure of an example of a decoder system that decodesan MPEG2 video bit stream reproduced from a recording medium, forexample an optical disc 15 on which an output of the foregoing videoencoder 10 has been recorded. Data reproduced from the optical disc 15by a reading portion 20 is digitally demodulated by a demodulatingportion 21. An ECC decoding portion 22 performs an error correction codedecoding process for an output of the demodulating portion 21. An outputof the ECC decoding portion 22 is supplied to a demultiplexer 23. Thedemultiplexer 23 demultiplexes the output of the demodulating portion 21into a video bit stream (V), an audio stream (A), and system information(S). The video bit stream (V) is input to an MPEG2 video decoderdesignated by reference numeral 24. The decoder 24 outputs a 24 Hz (or23.976 Hz) progressive moving picture to a video converting portion 25.The value of the frame rate is the same as frame_rate of the MPEG2 videobit stream.

A video signal that is output from the video converting portion 25 issupplied to a monitor 26. The monitor 26 displays the video signal. Acontrol signal that designates a display format of the display monitoris supplied to the video converting portion 25. The video convertingportion 25 converts the 24 Hz (or 23.976 Hz) progressive moving pictureinto a video signal having a designated display format.

FIG. 7 shows a list of converting processes performed by the videoconverting portion 25. Each converting method will be described in thefollowing.

For the converting processes performed by the video converting portion25, a converting process from 24 p into 30 i and a converting processfrom 24 p into 60 p are performed. As a result, intermediate signals of30 i and 60 p are generated. A signal reproduced from a disc is aprogressive signal (24 p) composed of 24 encoded frames per second. Theconverting process from 24 p into 30 i is the same as the 2:3 pull downconverting process described with reference to FIG. 3 except that thepicture size is in an HD format. In other words, a process forconverting two fields into three fields in accordance with apredetermined conversion pattern is performed. The first field isrepeatedly generated twice every five display frames. As a result, 24 pis converted into 30 i. When 24 p is converted into 60 p, the firstframe and the next frame are repeated twice and three times,respectively, every two frames of the 24 p encoded frames. As a result,a 60 p video signal is obtained.

FIG. 9 shows a converting process in the case that the display format isthe NTSC range and the disc format is 23.976 p. A converting processfrom 23.976 p into 29.97 i is a process for converting a progressivevideo signal having a frame rate of 23.976 Hz into an interlaced videosignal having a frame rate of 23.97 Hz. A converting process from 23.976p into 59.94 p is a process for converting a progressive video signalhaving a frame rate of 23.976 Hz into a progressive video signal havinga frame rate of 59.94 Hz.

When 23.976 p is converted into 29.97 i, like the converting processfrom 24 p into 30 i shown in FIG. 8, a 23.976 p encoded frame isconverted into an interlaced video signal by the 2:3 pull down process.When 23.976 p is converted into 59.94 p, like the converting processfrom 24 p into 60 p shown in FIG. 8, the first frame and the next frameare repeated twice and three times, respectively, every two frames ofthe 23.976 p encoded frames. As a result, a 59.94 Hz progressive videosignal is obtained.

FIG. 10 shows a converting process in the case that the display formatis the NTSC range and the disc format is 24 p. A converting process from24 p into 29.97 i is a process for converting a progressive video signalhaving a frame rate of 24 Hz into an interlaced video signal having aframe rate of 29.97 Hz. A converting process from 24 p into 59.94 p is aprocess for converting a progressive video signal having a frame rate of24 Hz into a progressive video signal having a frame rate of 59.94 Hz.

For the NTSC range, the converting process from 24 p into 29.97 i andthe converting process from 24 p into 59.94 i can be performed by addinganother process for 30 i generated from 24 p and a video signal as anintermediate signal of 60 p. Since there is a relation of 29.97 Hz(=30×(1000/1001) Hz), by thinning out one display frame from every 1001display frames of the 30 i signal, a 29.97 i signal can be generated. Inaddition, since there is a relation of (1/60)×1001×(1/1000)=(1/59.94),by thinning out one display frame from every 1001 display frames of the60 p signal, a 59.94 p signal can be generated.

Next, a practical example of the thin-out process will be described. A30 i signal for one minute is composed of 1800 display frames. Thus, bythinning out two frames every minute except for 0, 10, 20, 30, 40, and50 minutes, one display frame can be substantially thinned out fromevery 1001 display frames. As a result, a 29.97 i signal can begenerated. In addition, a 60 p signal for one minute is composed of 3600frames. Thus, by thinning out four frames every minute except for 0, 10,20, 30, 40, and 50 minutes, one display frame can be substantiallythinned out from every 1001 display frames. As a result, a 59.94 psignal can be generated. A process for not thinning out a display frameis normally referred to as a process for a drop frame.

FIG. 11 shows a converting process in the case that the display formatis the PAL range and that the disc format is 24 p. A converting processfrom 24 p into 25 i is a process for converting a progressive videosignal having a frame rate of 24 Hz into an interlaced video signalhaving a frame rate of 25 Hz. A converting process from 24 p into 50 pis a process for converting a progressive video signal having a framerate of 24 Hz into a progressive video signal having a frame rate of 50Hz.

When 24 p is converted into 25 i, the first 11 encoded frames and thelast one encoded frame are repeatedly displayed for two fields and forthree fields, respectively, every 12 encoded frames. As a result, aninterlaced video signal having a frame rate of 25 Hz is generated. When24 p is converted into 50 p, the first 11 encoded frames and the lastone encoded frame are repeatedly displayed for two frames and threeframes, respectively, every 12 encoded frames. As a result, aprogressive video signal having a frame rate of 50 Hz is generated.

FIG. 12 shows a converting process in the case that the display formatis the PAL range and that the disc format is 23.976 p. A convertingprocess from 23.976 p into 25 i is a process for converting aprogressive video signal having a frame rate of 23.976 Hz into aninterlaced video signal having a frame rate of 25 Hz. A convertingprocess from 23.976 p into 50 p is a process for converting aprogressive video signal having a frame rate of 23.976 Hz into aprogressive video signal having a frame rate of 50 Hz.

When 23.976 p is converted into 25 i, the first 11 encoded frames andthe last one encoded frame are repeatedly displayed for two fields andthree fields, respectively, every 12 encoded frames. In addition, onedisplay frame is inserted into every 1000 display frames. As a result,an interlaced video signal having a frame rate of 25 Hz is generated.When 23.976 p is converted into 50 p, the first 11 encoded frames andthe last one encoded frame are repeatedly displayed for two frames andthree frames, respectively, every 12 encoded frames. In addition, twodisplay frames are inserted into every 2000 display frames. As a result,a progressive video signal having a frame rate of 50 Hz is generated.

FIG. 13 is a flow chart applied for a reproducing method in the casethat the display format is the NTSC range and the disc format is 24 p or23.976 p. At the first step S101, it is determined whether the framerate of the disc format is 24 Hz or 23.976 Hz in accordance withinformation of a sequence layer of an MPEG2 video bit stream reproducedfrom the disc. When the frame rate is 24 Hz, the process advances tostep S102. When the frame rate is 24 Hz, the process advances to stepS105.

At step S102, it is determined whether or not the display format of themonitor is 29.97 i or 54.94 p. When the display format is 29.97 i, theprocess advances to step S103. When the display format is 54.94 p, theprocess advances to step S104.

At step S103, a converting process from 24 p into 29.97 i is performed.In other words, as described with reference to FIG. 8, two fields andthree fields are repeatedly displayed every two encoded frames. As aresult, a 30 i video signal is generated. In addition, as described withreference to FIG. 10, a process for thinning out one display frame fromevery 1000 display frames of the 30 i video signal is preformed. As aresult, an interlaced video signal having a frame rate of 29.97 Hz isgenerated.

At step S104, a converting process from 24 p into 54.94 p is performed.In other words, as described with reference to FIG. 8, two frames andthree frames are repeatedly displayed every two encoded frames. As aresult a 60 p video signal is generated. In addition, as described withreference to FIG. 10, a process for thinning out one display frame fromevery 1000 display frames of the 60 p video signal is performed. As aresult, a progressive video signal having a frame rate of 59.94 Hz isgenerated.

When the determined result at step S101 represents that the disc formatis 23.976 Hz, at step S105, it is determined whether the display formatof the monitor is 29.97 i or 54.94 p. When the display format is 29.97i, the process advances to step S106. When the display format is 54.94p, the process advances to step S107.

At step S106, a converting process from 23.976 p into 29.97 i isperformed. In other words, as described with reference to FIG. 9, aprocess for repeatedly displaying two fields and three fields every twoencoded frames is performed. As a result, an interlaced video signalhaving a frame rate of 29.97 Hz is generated.

At step S107, a converting process from 23.976 p into 54.94 p isperformed. In other words, as described with reference to FIG. 9, aprocess for repeatedly displaying two frames and three frames every twoencoded frames is preformed. As a result, a progressive video signalhaving a frame rate of 59.94 Hz is generated.

FIG. 14 a flow chart applied for a reproducing method in the case thatthe display format is the PAL range and the disc format is 24 p or23.976 p. At the first step S201, it is determined whether the framerate of the disc format is 24 Hz or 23.976 Hz in accordance withinformation of the sequence layer. When the frame rate is 24 Hz, theprocess advances to step S202. When the frame rate is 23.976 Hz, theprocess advances to step S205.

At step S202, it is determined whether the display format of the monitoris 25 i or 50 p. When the display format is 25 i, the process advancesto step S203. When the display format is 50 p, the process advances tostep S204.

At step S203, a converting process from 24 p into 25 i is performed. Inother words, as described with reference to FIG. 11, the first 11encoded frames and the last one encoded frame are repeatedly displayedfor two fields and three fields, respectively, every 12 encoded framesof 24 p. As a result, an interlaced video signal having a frame rate of25 Hz is generated.

At step S204, a converting process from 24 p into 50 p is performed. Inother words, as described with reference to FIG. 11, the first 11encoded frames and the last one encoded frame are repeatedly displayedfor two frames and three frames, respectively, every 12 encoded frames.As a result, a progressive video signal having a frame rate of 50 Hz isgenerated.

When the determined result at step S201 represents that the disc formatis 23.976 Hz, at step S205, it is determined whether the display formatof the monitor is 25 i or 50 p. When the display format is 25 i, theprocess advances to step S206. When the display format is 50 p, theprocess advances to step S207.

At step S206, a converting process from 23.976 p into 25 i is performed.In other words, the first 11 encoded frames and the last one encodedframe are repeatedly displayed for two fields and three fields,respectively, every 12 encoded frames. In addition, as described withreference to FIG. 12, one display frame is inserted into every 1000display frames. As a result, an interlaced video signal having a framerate of 25 Hz is generated.

At step S207, a converting process from 23.976 p into 50 p is performed.In other words, the first 11 encoded frames and the last one encodedframe are repeatedly displayed for two frames and three frames,respectively, every 12 encoded frames. In addition, as described withreference to FIG. 12, one display frame is inserted into every 1000display frames. As a result, a progressive video signal having a framerate of 50 Hz is generated.

Although the present invention has been shown and described with respectto a best mode embodiment thereof, it should be understood by thoseskilled in the art that the foregoing and various other changes,omissions, and additions in the form and detail thereof may be madetherein without departing from the spirit and scope of the presentinvention. For example, according to the present invention, the framerate of a video signal recorded on a recording medium may be fixed toone of 24 Hz or 23.976 Hz. In addition, the present invention can beapplied to the case that a movie source is converted into a video formatother than MPEG2. In addition, the present invention can be applied tothe case that bit stream data is recorded in a recording medium otherthan a disc, for example a semiconductor memory. In addition, the videoconverting portion 25 may be accomplished by software using amicroprocessor and a memory that stores a program as well as hardware.

Conventionally, when a video signal (having a frame rate of 29.97 Hz forthe NTSC range and a frame rate of 25 Hz for the PAL range) obtainedfrom a film material of 24 frames per second is encoded, differentprocesses are performed for the NTSC range and PAL range. In contrast,according to the present invention, a common encoding process can beperformed by a common encoder system for both the NTSC range and PALrange.

For the NTSC range, it was difficult to convert an interlaced movingpicture having a frame rate of 29.97 Hz into a progressive movingpicture having a frame rate of 59.94 Hz. In contrast, according to thepresent invention, a progressive moving picture is recorded on arecording medium. Thus, according to the present invention, for the NTSCrange, a progressive moving picture having a frame rate of 24 Hz or23.976 Hz can be easily converted into an interlaced moving picturehaving a frame rate of 29.97 Hz or a progressive moving picture having aframe rate of 59.94 Hz and displayed. In addition, according to thepresent invention, for the PAL range, a progressive moving picturehaving a frame rate of 24 Hz or 23.976 Hz can be easily converted intoan interlaced moving picture having a frame rate of 25 Hz or aprogressive moving picture having a frame rate of 50 Hz and displayed.

According to the present invention, for the PAL range, a problem ofwhich the reproduction speed of a video signal is faster than that ofthe original movie by (25/24 times). Thus, the reproduction speed of thevideo signal becomes the same as that of the original.

When a movie is taped by a HDTV video camera having a frame rate of 24Hz, according to the present invention, since a video material can bedirectly input to an MPEG video encoder, the video material can beconveniently handled.

DESCRIPTION OF REFERENCE NUMERALS

-   10 MPEG2 VIDEO ENCODER-   24 MPEG2 VIDEO DECODER-   25 VIDEO CONVERTING PORTION-   26 MONITOR-   S101, S201 Frame_rate=24 or 23.976 ?-   S102, S105 29.97 i or 54.94 p?-   S103 REPEATEDLY DISPLAY TWO FIELDS AND THREE FIELDS EVERY TWO    ENCODED FRAMES. IN ADDITION, THIN OUT ONE DISPLAY FRAME FROM EVERY    1000 DISPLAY FRAMES.-   S104 REPEATEDLY DISPLAY TWO FRAMES AND THREE FRAMES EVERY TWO    ENCODED FRAMES. IN ADDITION, THIN OUT ONE DISPLAY FRAME FROM EVERY    1000 DISPLAY FRAMES.-   S106 REPEATEDLY DISPLAY TWO FIELDS AND THREE FIELDS EVERY TWO    ENCODED FRAMES.-   S107 REPEATEDLY DISPLAY TWO FRAMES AND THREE FRAMES EVERY TWO    ENCODED FRAMES.-   S202, S205 25 i or 50 p?-   S203 REPEATEDLY DISPLAY FIRST 11 ENCODED FRAMES AND LAST ONE ENCODED    FRAME FOR TWO FIELDS AND THREE FIELD, RESPECTIVELY, EVERY 12 ENCODED    FRAMES.-   S204 REPEATEDLY DISPLAY FIRST 11 ENCODED FRAMES AND LAST ONE ENCODED    FRAME FOR TWO FRAMES AND THREE FRAMES, RESPECTIVELY, EVERY 12    ENCODED FRAMES.-   S206 REPEATEDLY DISPLAY FIRST 11 ENCODED FRAMES AND LAST ONE ENCODED    FRAME FOR TWO FIELDS AND THREE FIELDS, RESPECTIVELY, EVERY 12    ENCODED FRAMES. IN ADDITION, INSERT ONE DISPLAY FRAME INTO EVERY    1000 DISPLAY FRAMES.-   S207 REPEATEDLY DISPLAY FIRST 11 ENCODED FRAMES AND LAST ONE ENCODED    FRAME FOR TWO FIELDS AND THREE FRAMES, RESPECTIVELY, EVERY 12    ENCODED FRAMES. IN ADDITION, INSERT ONE DISPLAY FRAME INTO EVERY    1000 DISPLAY FRAMES.

1. An information processing apparatus for recording a video signal thatcan be displayed at all frame rates of 29.97 Hz, 59.94 Hz, 25 Hz, and 50Hz on a recording medium, comprising: compression encoding means forgenerating an encoded video bit stream having a size in common with anNTSC range and a PAL range, a frame rate of 24 Hz or 23.976 Hz, and aprogressive format; and recording means for recording the encoded videobit stream on the recording medium.
 2. An information processing methodfor recording a video signal that can be displayed at all frame rates of29.97 Hz, 59.94 Hz, 25 Hz, and 50 Hz on a recording medium, comprisingthe steps of: generating an encoded video bit stream having a size incommon with an NTSC range and a PAL range, a frame rate of 24 Hz or23.976 Hz, and a progressive format; and recording the encoded video bitstream on the recording medium.
 3. A program for an informationprocessing apparatus for recording a video signal that can be displayedat all frame rates of 29.97 Hz, 59.94 Hz, 25 Hz, and 50 Hz on arecording medium, the program comprising the steps of: generating anencoded video bit stream having a frame rate of 24 Hz or 23.976 Hz and aprogressive format; and recording the encoded video bit stream on therecording medium.
 4. A recording medium on which a computer readableprogram for an information processing apparatus for recording a videosignal displayed at a frame rate of 29.97 Hz, 59.94 Hz, 25 Hz, or 50 Hzis recorded, the program comprising the steps of: generating an encodedvideo bit stream having a size in common with an NTSC range and a PALrange, a frame rate of 24 Hz or 23.976 Hz, and a progressive format; andrecording the encoded video bit stream on the recording medium.
 5. Arecording medium on which a video signal that can be displayed at allframe rates of 29.97 Hz, 59.94 Hz, 25 Hz, and 50 Hz is recorded as acompression encoded video bit stream having a size in common with anNTSC range and a PAL range, a frame rate of 24 Hz or 23.976 Hz, and aprogressive format.
 6. An information processing apparatus forreproducing from a recording medium a compression encoded video bitstream having a picture size in common with an NTSC range and a PALrange, a frame rate of 24 Hz or 23.976 Hz, and a progressive format, theinformation processing apparatus comprising: means for reproducing theencoded video bit stream from the recording medium; decompressiondecoding means for decoding the reproduced encoded video bit stream andgenerating a video signal having a frame rate of 23.976 Hz or 24 Hz anda progressive format; and video converting means for converting anoutput of the decompression decoding means into a video signal having aframe rate of 29.97 Hz, 59.94 Hz, 25 Hz, or 50 Hz.
 7. The informationprocessing apparatus as set forth in claim 6, wherein when the displayformat is the NTSC range, the video converting means is configured toconvert the video having the frame rate of 24 Hz and the progressiveformat and output from the decompression decoding means into videohaving an interlaced format.
 8. The information processing apparatus asset forth in claim 6, wherein when the display format is the NTSC range,the video converting means is configured to convert the video having theframe rate of 24 Hz and the progressive format and output from thedecompression decoding means into video having a frame rate of 59.94 Hzand a progressive format.
 9. The information processing apparatus as setforth in claim 6, wherein when the display format is the PAL range, thevideo converting means is configured to convert the video having theframe rate of 24 Hz and the progressive format and output from thedecompression decoding means into video having a frame rate of 25 Hz andan interlaced format.
 10. The information processing apparatus as setforth in claim 6, wherein when the display format is the PAL range, thevideo converting means is configured to convert the video having theframe rate of 24 Hz and the progressive format and output from thedecompression decoding means into video having a frame rate of 50 Hz andthe progressive format.
 11. The information processing apparatus as setforth in claim 6, wherein when the display format is the NTSC range, thevideo converting means is configured to convert the video having theframe rate of 23.976 Hz and the progressive format and output from thedecompression decoding means into video having a frame rate of 29.97 Hzand an interlaced format.
 12. The information processing apparatus asset forth in claim 6, wherein when the display format is the NTSC range,the video converting means is configured to convert the video having theframe rate of 23.976 Hz and the progressive format and output from thedecompression decoding means into video having a frame rate of 59.94 Hzand the progressive format.
 13. The information processing apparatus asset forth in claim 6, wherein when the display format is the PAL range,the video converting means is configured to convert the video having theframe rate of 23.976 Hz and the progressive format and output from thedecompression decoding means into video having a frame rate of 25 Hz andan interlaced format.
 14. The information processing apparatus as setforth in claim 6, wherein when the display format is the PAL range, thevideo converting means is configured to convert the video having theframe rate of 23.976 Hz and the progressive format and output from thedecompression decoding means into video having a frame rate of 50 Hz andthe progressive format.
 15. A program for an information processingapparatus for reproducing from a recording medium a compression encodedvideo bit stream having a picture size in common with an NTSC range anda PAL range, a frame rate of 24 Hz or 23.976 Hz, and a progressiveformat, the program comprising the steps of: reproducing the encodedvideo bit stream from the recording medium; decoding the reproducedencoded video bit stream and generating a video signal having a framerate of 23.976 Hz or 24 Hz and a progressive format; and converting avideo signal obtained at the decompression decoding step into a videosignal having a frame rate of 29.97 Hz, 59.94 Hz, 25 Hz, or 50 Hz.
 16. Arecording medium on which a computer readable program for an informationprocessing apparatus for reproducing from a recording medium acompression encoded video bit stream having a picture size in commonwith an NTSC range and a PAL range, a frame rate of 24 Hz or 23.976 Hz,and a progressive format is recorded, the program comprising the stepsof: reproducing the encoded video bit stream from the recording medium;decoding the reproduced encoded video bit stream and generating a videosignal having a frame rate of 23.976 Hz or 24 Hz and a progressiveformat; and converting a video signal obtained at the decompressiondecoding step into a video signal having a frame rate of 29.97 Hz, 59.94Hz, 25 Hz, or 50 Hz.